JPH0284483A - Adhesive composition - Google Patents

Abstract

PURPOSE:To obtain a novel adhesive composition excellent in adhesiveness of synthetic resin molded products, such as especially PP or PE, or molded products coated with the above-mentioned resin to various labels by adding a specific amount of a surfactant to an aqueous dispersion of a bonding resin. CONSTITUTION:The objective composition obtained by adding (B) 2-30 pts. wt. (especially preferably 5-20 pts.wt.) nonionic surfactant, such as fatty acid esters of higher alcohols, etc., to (A) 100 pts.wt. (expressed in terms of the total solid content) aqueous dispersion of a bonding resin consisting of a synthetic resin emulsion, such as vinyl acetate resin or acrylic copolymer resin, synthetic or natural rubber-based emulsion or rosin-based resin emulsion.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a novel adhesive composition, which is used for adhering synthetic resins to various porous materials such as paper, wood, and foamed plastics. In particular, the present invention relates to materials suitably used for bonding various types of labels and the like to molded products made of various synthetic resins or molded products coated with various synthetic resins.

[Conventional technology/problems to be solved] In recent years, various plastic containers, especially polyethylene,
Polyolefin bottles represented by polypropylene (hereinafter referred to as rPEJ and rPPJ, respectively) and polyethylene terephthalate (hereinafter referred to as rPETJ) bottles, as well as bottles with polyolefin coating on the surface, cans, paper bags, paper cartons, and synthetic paper are widely used. However, when attaching various labels etc. to such molded products, the surface of the synthetic resin and the paper surface,
In some cases, it may be necessary to bond the polyolefin surfaces together.

Traditionally, vinyl acid, acrylic ester, and ethylene/vinyl acetate copolymer emulsions have been used as adhesives for labels, but although these adhesives are good for bonding paper to paper, The adhesion between the polyolefin surface and the paper surface and the adhesion between the polyolefin surfaces are extremely poor.

Furthermore, the adhesives that make these adhesives possible have various problems when, for example, labeling various containers, laminating them, and making boxes. That is, when labeling with a current labeling machine, normally 10-300bp10
-300bp perminute) to 60
When laminating using various methods using a laminator, the speed ranges from 10 to 250 m/min, and the same situation exists when making boxes and bags using sack machines, etc. Although there is a demand for even higher speeds in order to further increase productivity, various problems have arisen with this type of adhesive due to the increased bonding speed. The emulsion is destroyed by mechanical shearing force during pump transportation for supplying it, and when bonding with various adhesive rolls and plates, resulting in the formation of coarse particles and foam solidification due to the foaming of the emulsion, and the resulting generation and scattering of scum. Stringing, etc. may occur, and in some cases, gum up may occur on various adhesive rolls and plates, causing work to be interrupted to clean them, resulting in a decrease in productivity and unevenness on the tag-attached product, resulting in product damage. Serious problems such as a decline in quality have occurred.

[Means for Solving the Problems] As a result of intensive research into reliably adhering to synthetic resins, as well as solving problems related to the functional suitability of adhesives and mechanical stability at high speeds, the present inventors have developed various aqueous dispersions. By adding a relatively large amount of surfactant to the adhesive, it becomes possible to bond to polyolefin and other synthetic resins (including rubber), and also solves the aforementioned problems in mechanical suitability, resulting in even better properties. They have found that results can be obtained and have completed the present invention. In other words, conventionally, surfactants have been used in adhesives in amounts of less than 0.1%, and surfactants are used to prevent adhesion. It was thought that adding a large amount would have a greater negative effect on adhesion, such as a decrease in initial adhesive strength, loosening, and in some cases gelation and formation of coarse particles, but surprisingly, The inventor discovered that by adding a certain amount of surfactant, adhesives that conventionally did not adhere to plastic surfaces such as polyolefins exhibited good adhesive properties, and also improved workability such as mechanical suitability and washability. They discovered that it also exhibited excellent performance.

In the present invention, for an aqueous dispersion of an adhesive resin or a mixture of an aqueous liquid of a natural or synthetic polymer having compatibility therewith, approximately 2
By adding ~30 parts by weight of a surfactant, the adhesion is excellent not only between paper surfaces, but also between polyolefin and other plastics (including rubber) and paper and polyolefin and other plastic surfaces, and is even better than conventional adhesives. It has good washability without the observed deterioration in water washability, and it is also possible to form an adhesive layer with excellent water resistance that does not easily peel off even when the adhesive is completely immersed in water. When gluing the above plastic surfaces together, it takes some time to bond because the moisture evaporates from the adhesive slowly, but if one side is made of foam or has a bottle hole or other through hole, then it will take some time. , and can be more easily adhered.

The adhesive resin aqueous dispersions produced by the company include vinyl acetate resin, modified vinyl acetate resin, modified vinyl acetate/ethylene copolymer resin, vinyl acetate/ethylene copolymer resin, vinyl acetate/ethylene/vinyl chloride copolymer resin, and acetic acid. Synthetic resin emulsions such as vinyl-acrylic copolymer resins and other vinyl acetate copolymer resins, acrylic copolymer resins, acrylic-styrene copolymer resins and other acrylic copolymer resins,
There are synthetic rubber emulsions, natural rubber emulsions, rosin resin emulsions, etc., and these may be used alone or in a mixture of two or more. Such an aqueous dispersion is usually used with a resin solid content of about 25 to 75% by weight, particularly preferably 35 to 65% by weight.

Aqueous liquids of natural or synthetic polymers that are compatible with the above aqueous dispersion include saponified or partially saponified polyvinyl alcohol (PVA), gelatin, cellulose derivatives such as water-soluble methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropyl methyl cellulose, etc.), polyvinylpyrrolidone and polyacrylic acid, polyacrylic acid amide, starch (e.g. potato starch, corn starch, wheat starch, rice starch,
tapioca starch, etc.), modified starch (e.g. soluble starch, oxidized starch, acetate starch, phosphorylated starch, etc.), dextrin,
There are dextrin derivatives, etc., and these are used singly or in a mixture of two or more kinds, typically about 0.5 to 40% by weight (or more if highly soluble) in water.

The above-mentioned adhesive resin aqueous dispersion is generally preferably used at a solid content equal to or less than that, but it may be added in some cases.

Surfactants are mainly fatty acid higher alcohols, alkylphenols, and fatty acids condensed with ethylene oxide; in other words, aromatic surfactants include polyoxyethylene alkylphenyl ether (e.g., polyoxyethylene octylphenyl ether, polyoxyethylene octylphenyl ether, nonylphenyl ether, etc.), higher alcohols,
Polyoxyethylene alkyl ether (e.g. polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether,
polyoxyethylene oleyl ether, etc.), fatty acid derivatives include sorbitan fatty acid esters (for example, sorbitan monostearate, sorbitan monolaurate, sorbitan monooleate, sorbitan monopalmitate, sorbitan tristearate, sorbitan trioleate,
sorbitan sesquioleate, etc.), polyoxyethylene sorbitan fatty acid esters (e.g. polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan monovalmitate, polyoxy tristearate) Nonionic types such as ethylene sorbitan, polyoxyethylene sorbitan trioleate, etc.) and polyoxyethylene acyl esters (e.g., polyethylene glycol monolaurate, polyethylene glycol monostearate, etc.) are used, but anionic types are also used. These can be used alone or in a mixture of two or more. This surfactant is added in an amount of about 2 parts by weight or less based on 100 parts by weight of the total solid content of the aqueous adhesive resin dispersion or the mixture thereof with an aqueous natural or synthetic polymer liquid. If the amount is more than about 30 parts by weight, the adhesion ability will decrease and it is not practical.
It is preferable to add 0 parts by weight.

In addition, adhesive strength, adhesion strength, etc. can be adjusted by adding a plasticizer or tackifier to this adhesive composition. Examples of such plasticizers include dibutyl phthalate, butyl benzyl phthalate, etc. Phthalate esters such as J, phosphate esters such as tricresifle phosphate, trioctyl phosphate, dioctyl adipate,
Fatty acid dibasic esters such as dioctyl succinate, cellosolves and carpitol such as butyl carpitol acetate, benzyl alcohols, glycol monophenyl ethers, etc. are used. Further, as the tackifier, terpene resin, rosin resin or its derivatives, petroleum resin, etc. can be used.

In addition, if necessary, preservatives, antifungal agents, antifreeze agents, pH
Conditioners, antifoaming agents, etc. may be used as appropriate.

[Example] Example 1 Vinyl acetate/ethylene copolymer resin with a solid content of 50% by weight (
Acrylic copolymer resin emulsion 10 (ethylene content 15%) emulsion 100 parts by weight, solid content 50% by weight
0 parts by weight, 50 parts by weight of rosin resin emulsicone with a solid content of 50% by weight were mixed and stirred at room temperature, and further 6 parts by weight of polyoxyethylene nonylphenyl ether was added, and 1 part by weight of an acrylic acid ester emulzidine type thickener was added. An adhesive composition was obtained. Incidentally, the thickener was added in the following examples in order to eliminate the influence of viscosity on the adhesive action (the same applies hereinafter).

Example 2 Example 1 except that the above-mentioned surfactant was added in an amount of 12 parts by weight.

Example 3 Example 1 except that the above-mentioned surfactant was added in an amount of 18 parts by weight.

Example 4 Example 1 except that the amount of the surfactant added was changed to 24 parts by weight.

Example 5 Example 1 except that the above-mentioned surfactant was added in an amount of 30 parts by weight.

Example 6 In Example 1, a vinyl acetate resin emulsion with a solid content of 40% by weight was used instead of the vinyl acetate/ethylene copolymer resin emulsion, an acrylic acid ester thickener was not used, and the above-mentioned surfactant was used. An adhesive composition was obtained by blending the same formulation as in Example 1, except that the amount added was 12 parts by weight.

Example 7 Example 6 except that the above-mentioned surfactant was added in an amount of 18 parts by weight.

Example 8 Example 6 except that the above-mentioned surfactant was added in an amount of 24 parts by weight.

Example 9 Example 1 was repeated, except that soluble starch with a solid content of 35% by weight was used instead of the vinyl acetate/ethylene copolymer resin emulsion, and the amount of the surfactant added was 12 parts by weight. An adhesive composition was obtained by blending the same formulation as 1.

Example 10 Example 9 except that the above-mentioned surfactant was added in an amount of 18 parts by weight.

Example 11 In Example 1, except that a modified vinyl acetate ethylene copolymer resin emulsion with a solid content of 50% by weight was used instead of the acrylic copolymer resin emulsion, and the amount of the above-mentioned surfactant added was 18 parts by weight. The same formulation as in Example 1 was used to obtain an adhesive composition.

Example 12 In Example 11, the amount of the surfactant added was increased to 24
By weight.

Example 13 Example 1 was repeated, except that a styrene-butadiene rubber emulsion with a solid content of 50% by weight was used instead of the acrylic copolymer resin emulsion, and the amount of the surfactant added was 18 parts by weight. An adhesive composition was obtained by blending the same formulation as 1.

Implementation PA14 In Example 13, the amount of the above-mentioned surfactant added was 24%.
By weight.

Example 15 In Example 1, a modified vinyl acetate/ethylene copolymer resin emulsion with a solid content of 52% by weight was used instead of the rosin resin emulsion, and the amount of polyoxyethylene oleate ester added was 18 parts by weight. , Example 1
and the same formulation to obtain an adhesive composition.

Example 16 In Example 1, a modified acrylic copolymer resin emulsion with a solid content of 52% by weight was used instead of the rosin resin emulsion, and the amount of polyoxyethylene sorbicun monolaurate added was 18 parts by weight. The same formulation as in Example 1 was used to obtain an adhesive composition.

Example 17 Acrylic copolymer resin emulsion 2 with solid content of 50% by weight
To 50 parts by weight, 18 parts by weight of polyoxyethylene nonylphenyl ether and 1 part by weight of an acrylic acid ester emulsion type thickener were added, and an adhesive composition was obtained in the same manner as in Example 1.

Regarding the adhesive compositions of the above examples, (1) to (
Measurements and tests were conducted regarding the items shown in 6). The results are shown in Table 1.

(1) Viscosity, measured using a Visco Tester (manufactured by Rion Co., Ltd.) according to JIS K6838.

(2>pH, according to JIS K6837.

(3) Solid content: According to JIS K6839.

(4) Adhesiveness test This adhesive composition was applied to an oval label made of 46-size, 73 kg Z-ream piece art paper using a pal coater Nα7 at a coating amount of 15 to 20 g/rd, and immediately put on the market. PET film (thickness 0°1) and PE film (
A plurality of sheets were laminated to a PP film (thickness 1.1 cm) and a PP film (thickness 1.1 cm), lightly brushed, and cured for 24 hours in an atmosphere of f&20°C and 265% RH.

In addition, PE coated glass bottles (bottles)
, and affixed it to an epoxy painted can using the same procedure. After curing, the label was forcibly peeled off with fingers, and the adhesion was evaluated based on the broken area (area of the label piece remaining on the surface of the adherend or paper broken area).

(5) Water resistance test For those that showed good adhesion to various adherends, the adhesive of the three types of films PE, PP, and PET used in the adhesion test and the label were placed in water at 30°C. Completely immersed, 1
Forced peeling was performed in water every hour, and the time until the paper peeled off from the adhesive surface without tearing was recorded.

(6) Dry and semi-dry films attached to the stirrer used in the production of the cleansing adhesive composition, the bar coater used in the test, and various machines (labeling machines, etc.) used to confirm mechanical suitability. It was investigated whether or not such substances and aggregates could be removed with water or hot water.

Comparative Examples 1 to 8 In Examples 1, 6, 9, 11, 13, 15, 16, and 17, adhesive compositions were obtained by blending the same formulations as in Examples, except that the above-mentioned surfactant was not blended. Ta.

These products were subjected to the same tests as in the examples. The results are shown in Table 2.

The storage stability of the adhesive composition of the example was extremely good, and no change in viscosity or appearance was observed even after 6 months.

(Discussion) It can be seen that by adding a considerable amount of surfactant, good adhesive performance is expressed, and good results are also obtained in terms of water resistance and washability.

Table 1 Example test results

Claims (1)

[Claims] 1. It is characterized in that 2 to 30 parts by weight of a surfactant is added to 100 parts by weight (total solid content) of one or more types of adhesive resin aqueous dispersion. Adhesive composition. 2. 2 to 30 parts by weight of surfactant per 100 parts by weight (as total solid content) of a mixed solution of one or more types of adhesive resin aqueous dispersion and an aqueous liquid of a natural or synthetic polymer compatible therewith. Adhesive composition characterized by adding part. 3. The adhesive composition according to claim 2, wherein the adhesive resin aqueous dispersion is contained in an amount equal to or more than the solid content of the natural or synthetic polymer aqueous liquid. 4. The adhesive composition according to any one of claims 1 to 3, wherein the surfactant is a nonionic surfactant.